Cambridge Professional English Infotech English for computer users Fourth Editiorf

How screen displays work

Displays, often called monitors or screens, are the
most-used output device on a computer.They provide instant feedback by showing you text and graphic images as you work or play.
Most desktop displays use Liquid Crystal Display (LCD) or Cathode Ray Tube (CRT) technology, while nearly all portable computing devices, such as laptops, incorporate LCDs. Because of their slimmer design and lower energy consumption, LCD monitors (also called flat panel or flat screen displays) are replacing CRTs.
Basic features
Resolution refers to the number of dots of colour, known as pixels (picture elements), contained in a display. It is expressed by identifying the number of pixels on the horizontal and vertical axes. A typical resolution is 1024x768.


A pixel is a combination of red, green and blue subpixels

Two measurements describe the size of your display: the aspect ratio and the screen size. Historically, computer displays, like most televisions, have had an aspect ratio of 4:3 - the width of the screen to the height is four to three. For widescreen LCD displays, the aspect ratio is 16:9, very useful for viewing DVD movies, playing games and displaying multiple windows side by side. High- definition TV also uses this format.The viewable screen size is measured diagonally, so a 19"screen measures 19" from the top left to the bottom right.

Inside the computer there is a video adapter, or graphics card, which processes images and sends signals to the monitor. CRT monitors use a VGA (video graphics adapter) cable, which converts digital signals into analogue signals. LCD monitors use a DVI (digital video interface) connection.